Improving the conductivity and tensile strength of copper and its alloys.



UNITED STATES PATEN OFFICE.

RUDOLF FRANKE, OF EISLEBEN, GERMANY, ASSIGNOR T0 ELEKTROCHEMISCHE WERKE (G. M. B. IL), OF BERLIN, GERMANY.

IMPROVING THE CONDUCTIVITY AND TENSILE STRENGTH OF COPPER AN D ITS ALLOYS.

No Drawing.

copper and its alloys for electrical conduc-' tors in such manner as to increase both the tensile strength and the electrical conductivity thereof.

The sales department of the German Copper \Vire Association deals in copper wires having the following physical characteristics:

Tensile strength per per sq. mm., kg. Cortlductiv- 1 y r cent}: cc. Soft Hard wires, drawn cc. wires, cc.

1. Chemically pure copper wires. 95-100 24 40-45 2. Bronze wires for telephone and telegraph circuits: (a). 40-40 (b). -52 (0). 68-71 ((1) 65-78 (e) 78-84 3. Double bronze wires of any desired quality.

The grades designated under 2 (b) and (c) are mainly used by the German Imperial Pcstal Department and by other governmental postal and telegraphic bureaus, i2 (7)) in sizes from 2 to 4 mm., to connect the several telephone. systems with each other, and 2 (c) oftl'i'e size of 1.5. mm. for the connections within the telephone systems themselves.

The tensile strength of the several grades Specification of Letters Patent.

Application filed April 4, 191-0. Serial No. 553,339.

of bronze wire difi'ers according tothe size of the wire; it increases as the diameter di minishes, and decreases as the diameter increases.

Phosphorus or phosphor-copper serves as an addition for the chemically pure copper wires; a composition, together with a partial addition of tin, for the harder wires; and, for the double bronze wires, always said composition and tin. The composition referred to consists of 64% aluminum and 36% magnesium. Whether said composition is capable of being replaced by calcium, or by molybdenum has been made the subject of the tests hereinafter referred to. In these tests, electrolytic copper of the best quality was exclusively employed, and hard-drawn wire as well as soft (annealed) wire was produced by the drawing operation, as follows: 1. \Vires without any addition. 2. Wires with the addition of calcium in the form of calcium-copper. 3. Wires with the addition of molybdenum in the form of molybdenum powder. 4. Wires with the addition of aluminum and calcium. 5. Wires with the addition of molybdenum and calcium, (the calcium in the form of calciumcopper) and 6. Wires with the addition of aluminum-molybdenum-calcium,' (the calcium in the form of aluminum-calcium, and the molybdenum as a powder.) The one portion of the wires remained hard-drawn, the other was annealed. and both kinds, in the hard-drawn and soft condition respectively, Were tested with regard to their physical properties. With the facilities at hand the wires could only be drawn 3/4 hard, for which reason it has been found necessary to revise the calculation to l/1 The additions had the following composition: (a) calciumcopper=12.2% of Ca; (6) molybdenum powder:97.1% of Mo and 34% of oxid, 1.4% insoluble matter, 0.65% Fe and Al as carbid; aluminumcalcium:42.3% of Ca, 55.85% of Al, 1.85% insoluble matter. It may be noted here that, asis Well known,

Patented Apr. 18, 1911.-

Torslon at 75 B endings over 9 3 n88 998 mal Conducdlus tlvlty.

Resistance.

Resistance.

QQLLLQQLLZQO 111111111111 M ZAQG 46582 xowaomannoums he results obtained are summarized in following tables:

Tensile stren;,th.

mm. mm.

Hard-drawn wires.

Per sq.

3/4 hard.

l the Tensile strength.

Cross section.

AlCa.

Weight per m.

Additions.

AlCa.

Copper wires.

Additions.

Copper wires.

Seria number.

molybdenum has the property of making copper harder.

Serial number.

mlnum-magnesium comgrade of copper. 2. The hard-drawn wires tivity.

without any addition whatts of the chemically pure copper ever, from such a Conducfor which the requirements are Cpndue- Tensile strength tivity. per sq. mm., hard.

s of the alu ance of the purity of the electrolytic copper employed, and shows what p can be obtained the first instance under 2 a and b heretofore produced by the addition of corresponding 115 quantitie position,

These requirements are fulfilled by Soft.

Tensile strength.

Soft.

Tensile strength.

Conductivity.

Conductivlty.

From the foregoing tables it appears 1. The wires designated by Serial No. 1, and without any addition, correspond to the requiremen wires listed in the first which have been customarily produced by theaddition of calcium the addition of a certain amount of phosphorus or phosphor-copper, and for which the requirements are These requirements are fulfilled with This determination serves as an assnr- -copper is far superior to the aluminum-magnesium composition.

3. The hard-drawn wires produced with the addition of molybdenum and bearing Serial Nos. 5 to 7 correspond, with a molybdenum addition up to 0.35% maximum to the requirements of the hard-drawn bronze wires heretofore produced with the addition of corresponding quantities of the aluminum-magnesium composition and listed in the first instance under 2 a and 2 b, for which the conditions are as follows;

Conduc- Tensile strength tivlty; per sq. mm., hard.

Kg. Under 2a.. 95 40-46 Under 2b. .85 50-52 These conditions are fulfilled by:

Tensile strength per sq. Inm., hard.

Conductivity.

tensile strength and is in no wise prejudicial to conductivity. This determination shows that molybdenum (preferably to be added as molybdenum-copper) is far superior to the aluminum-magnesium composition and has properties quite. similar to those of calcium.

4. The hard-drawn wires produced with the addition of aluminum-calcium and bearing Serial Nos. 8 to 10 correspond, it is true, in general with the hard-drawn wires produced with the addition of corresponding quantities of the aluminum-magnesium composition listed in the first instance under 2a and 27), but show the unfavorable influence of the aluminum upon their conductivity. For this reason, this addition should not be employed.

5. The hard-drawn Wire produced with a calcium-molybdenum addition and bearing Serial No. 11 corresponds, With an addition of molybdenum and calcium addition (of each 035%,) to the requirements of the hard-drawn bronze wires produced by the addition of corresponding quantities of the aluminum-magnesium composition listed in the first instance under 2a and 2b, and combines the good qualities which calcium and molybdenum develop when individually employed. With this combined addition of say 0.35% (as against the addition of the aluminum-magnesium composition), harddrawn Wires of a tensile strength up to 52 kg. per sq. mm. and with a conductivity of 98% can be produced.

6. The hard-drawn wire produced with an addition of aluminum-calcium-molybdenum, (made up of 0.35% each. of aluminum-calcium and molybdenum) manifests the favorable influence due to molybdenum and calcium, but, in consequence of the presence of the aluminum, does not exhibit those good qualities which calcium and molybdenum when employed alone develop. For this reason, this addition should not be used.

These tests have established the extraordinarily valuable pr osition, (1), that calcium and molybdenum ddition can be advantageously substitutedior the aluminummagnesium composition heretofore employed for hard-drawn bronze wires, (2) that, (in contrast to additions heretofore employed) with an addition of at the most 0.35% of calcium, or of molybdenum, or of both metals, hard-drawn wires can be produced with at least 50 to 52 kg. per sq. mm. tensile strength and with a conductivity of 95%, and (3) that, in view of the good qualities of calcium and molybdenum, it is advisable to produce the conditions referred to in the first instance under 1 corresponding to chemically pure copper wires, not by the addition of phosphorus or phosphor copper, but by means of a moderate (say 0.05 to 0.10%) addition of calcium or molybdenum or an addition of both metals. For tele phone and telegraph purposes these results,

which have never before been obtained, are of the most far-reaching importance.

As hereinbefore stated, the sales branch of the German Copper Wire Association also deals in bronze wires, for telephone and telegraph circuits, having the following physical properties:

Hard-dmwnbronze @UiTGSr-QO with conductivity and 6871 kg. tensile strength per sq. mm, 2d with 40% conductlvity and 78 kg. tensile strength per sq. mm. 25 with 30% conductivity and 78-84 kg. tensile strength per sq. mm. For these bronze wires, a composition of 64% aluminum and 36% magnesium serve as the addition in connection with tin. By the following tests, it was to be determined, whether, in the presence of tin, the said composition should tion of Ca, (2) bronze wires of Cu and Sn with the addition of Mo, (3) bronze wires of Cu and Sn with the addition of Ca and M0. The one portion of the wires remained hard-drawn, and the other portion was annealed, and both kinds in their hard-drawn and soft condition were investigated as to their physical properties. With the facilities at hand the wires could only be drawn 3/4 hard; it was therefore necessary to revise the calculation to 1/1. The calcium was used in the form of calcium-copper, and the molybdenum in the form of mol bdenum be supplanted by calcium or molybdenum or powder. The additions had the ollowing by both metals. In these tests, electrolytic composition; (a) Calc1um-copper=12.2% copper and tin of the best quality were emcalc1um,=97.2% Mo, with 34% OXld; ployed, and hard-drawn wires as well as molybdenum 1.4% insoluble matter, soft (annealed) wlres were produced, in 0.65% Fe and Alas carbid. such manner, that there were drawn, (1). The results obtained are summarized in bronze wires of Cu and Sn wlth the addithe followlng tables:

Composition. HaId dmWn bronze wires.

Tensile strength. Resistance.

13 1/1 3 35? Tor 0. C C M Sn Weight 2:: a/lhard' hard. upon sion 11. n. o. pen on 9 Com M75 7 1000. dius mm.

At Per For m. tivity. 150 sq. sq. mm. mm. mm.

5 a. s .455. Kg. K9. K0. 7

Composition. Soft (annealed) bronze wires.

Tensile Resistance Flex Ser. No. strength. urea Wgt. Cross upon sion MO perm. section. araat75 At 50 Per sq. .0 1000 Conducdius mm. mm. mm. m. tivity. 5.

% 0. Sq. mm Kg. Kg. 0.5 18 1.5 58 28.8 9.9 85.5 18 48 1. 0 15.8 1. 525 55 80. 8 12. 2 77 14 50 1. 5 18. 05 1. 505 50 29. 7 14. 7 57. 5 17 49 2. 0 17. 85 1. 595 58 84 18. 4 45. 5 15 42 0. 5 17.55 1. 58 58 84. 5 10. 5 82 15 42 1.0 15.55 1.585 54 84.7 .158 58.5 15 80 1. 5 15.55 1. 545 75 40. 5 19. 2 47. 5 18 45 2. 0 15.15 1. 515 55 36. 7 25. 4 40.5 17 40 0.5 18.2 1.51 52 80.5 11.1 71.5 18 55 1. 0 15.15 1. 5 15 48 17. 5 55 18 85 1. 5 15.1 1. 51 89 21. 8 44. 5 20 28 2.0 11.2 1.57 72 87.2 28.1 88.5 18 19 If we arrange the drawn Wire grades according to the tin additions, We obtain the I. Wires with 0.6 Sn.

following groups d m M m w. w 5 M m "w W 8 9 9 1 l l 1 1 m .EE E. 3 2 8 QQ$ e 58 w n s WWW m E 3 25.8 Q%% m 85 as a "B B um m n .m 0 0 0 0 r. l I b m -E 868 r w m: 3 468 b 6 mafia. 80 b mmiuwu 67 m a 89. E 111 W a d2; mafia 111 m can mSEG 12 Q a non: 555g 11 .w m 5 5 M 5 m w 555 .w m 555 a. mw 53:03.58 %&H mm QE E Q %w. m m 5:5 38 %muu mw $5 2 0 %mm s w m 4 m m E .5 m 55 3 5m WMMB m 3 5m wmmm m EE 5 8m 9 S nu b 338 K S npwdo m ommmwa K S numaw m 0:25 K S nuwnm m S 5 K 310 423 n 933 999 .55 ms 3 8 8 111 85 3 33:5. 111 M 58 3 H220 1 1 n E8 3. 3 53.8 m v "M m W m W0 m m E n Q: E 32 L Y m 3 3 718 4 @3 2 219 w a men: 332 1 1 W w a non: mwusw m 11 m W a menu 855 1 m e a mom: $555 11 z z z n m w w m m 3352 80 7 4 1% m m m B as no %M74 w m m 3 :0 rh w m h bsouwnoo %M29 b 887 w b a .5 e o 4 75s b Q. a b 443 .W 4 m a 13 W m u L m a 4 s m u m im 63 H: ma a L m m p 65 S Mama H v m m e3 3 nwnw I m mmim e5 5 umn d t t I .l d h d t m m nfl .m mn m m mm.v a n g H ms v d H 3 9m H ha 4 an H m is has a w s KMM4 m in: K455 m X455 n K 55 55 v o .33 a o Ea o M 0 0 M m n M 5 m5 Mn m m M "m m o we "m m L h u L H L m e m a H h n M Ma Ib 1b lb a m n u n mm 1 H m H m S 59 S S S u n n y 1 n n 0 0 5 0 5 0 5 0 5 1 H W PM 3 3 4 4 5 5 6 bronze Wires, only the results as to the hard drawn Wires need be considered. Neverthe- From a practical standpoint, in arriving, at a determination of the quality of these less, although the results as to the soft bronze wires are without practical importance, they are theoretically significant inasmuch as they justify direct COIIClllSlOIlS as to the etfect of the foreign ingredients.

The results as to the hard drawn Wires permit the following conclusions: 1. Qualities may beobtained which not only meet the conditions prescribed by 20 to 26 of the German Copper Wire Association, but which, together with extraordinary tenslle strength, exhibit even higher conductivit es. 2. In the presence of tin, the compositlon of 64% aluminum and 36% magnesium may be supplanted by calcium, or by molybdenum, or by both metals. 3. In the production of the wires, according as it is desired to impart thereto (1) tensile strength, or (2) conductivity, the procedure should be as follows: (a) If we desire higher-conductivity with appropriate tensile strength, we should use as the addition tin in quantities of 0.5 to 2.0%, and constantquantities of calcium of 0.35%. (b) If we desire higher tensile strength with appropriate conductivity, we should use as the addition tin in quantities of 0.5 to 2.0% and constant quantities of molybdenum of 0.35%. (0) If we desire specially high tensile strength we should use as the addition tin (1n quantities of 0.5 to 2.0%) and both calcium and molybdenum, in constant quantities of each 0.35%.

The making up of the alloys for hard drawn bronze wire, takes the following shape, according to the foregoing conclusions:

Se- Stress is laid upon: 115:1 g g Sn. Ca. Mo.

' 7 '7 a '7 Higher conductivity.... 1 8 58.7 0. 5 0.3 5: Highertensilestrength.. a 81 59.1 0.5 0.35 Specially high tensile strength 9 70.5 64.5 0.5 0.35 0.35

Higherconductivity.... 2 75.5 65.7 1.0 0.35 Highertensilestrength.. 6 57 66.7 1.0 0.35 Specially high tensile strength 10 54 67.6 1.0 0.35 0.35

Highei'conductivity.... 3 57 05.4 1.5 035 'Highertensilestrength 7 48 74 1.5 0 35 Specially high tensile strength 11 43 78.7 1.5 0.35 0.35

Higher conductivlty.... 4 45.5 74.7 2.0 0.35 Highertcnsilestrength.. 8 42 78.8 2.0 0.35 12 30 73.3 20 0.35 0.35

molybdenum additions, new intermediate 1 grades as to conductivity and tensile strength may be produced, by using tin additions of 0.25, 0.75, 1.25 and 1.7 5%.- This affords the possibilityof not only fulfilling the conditions of 20 to 26 of the German Copper Wire Association, but of producing a great number of new grades wherein conductivity and tensile strength stand in a more advantageous relationship to each other.

In the appended claims it is to be understood that by copper I mean any alloy wherein copper preponderates.

Having thus described my invention, What I claim is:

1. The method of improving copper for the purpose described, which comprises adding calcium thereto in such proportion as to increase the tensile strength and conductiv ity thereof; substantially as described.

2. The method of increasing the tensile strength and conductivity of copper, which comprisesadding less than 1 per cent. of calcium thereto; substantially as described.

3. The method of increasing the tensile strength and conductivity of copper, which comprises adding substantially .35 per cent. of calcium thereto; substantially as described.

4. The methodof improving copper for the purpose described, which comprises adding calcium and molybdenum thereto in such proportions as to increase the tensile strength and conductivity thereof; substantially as described.

5. The method of increasing the tensile strength and conductivity of copper, which comprises adding less than 1 per cent. of calcium and less than 1 per cent. of molybdenum thereto; substantially as de scribed. 6. The method of increasing the tensile strength and conductivity of copper, which comprises adding substantially .35 per cent. of calcium and substantially .35 per cent. of molybdenum thereto; substantially as described.

7. An alloy for electrical conductors having a preponderating proportion of copper and such a proportion of calcium that the v tensile strength and conductivity are increased; substantially as described.

8. An alloy for electrical conductorshaving a preponderating proportion of copper, and less than 1 per cent. of calcium, whereby the tensile strength and conductivity are increased; substantially as described.

9. An alloy for electrical conductors having a preponderating proportion of copper, and substantially .35 per cent. of calcium, whereby the tensile strength and conductivity are increased; substantially as described.

10. An alloy for electrical conductors having a preponderating proportion of copper and such a proportion of calcium and molybdenumthat the tensile strength and conductivity are increased; substantially as described.

11. An alloy for electrical conductors having a preponderating proportion of copper,

less than 1 per cent. of calcium and less than whereby the tensile strength and conductiv- 1 per cent. of molybdenum, whereby the tenity are increased; substantially as described. 10

sile strength and conductivity are increased; In testimony whereof I aflix my signature, substantially as described. in presence of two Witnesses.

12. An alloy for electrical conductors hav- RUDOLF FRANKE. ing a preponderating proportion of copper, Witnesses: substantially .35 per cent. of calcium and RUDOLPH FRIOKE,

substantially .35 per cent. of molybdenum. SOUTHARD P. WARNER. 

